Keysight Technologies X Series Service Manual page 159

RF Section Troubleshooting (RF/Microwave Analyzers)
Troubleshooting
4. Input Attenuator A Control Logic Verification
— Press AMPTD, Attenuation 0 dB
All the attenuation LED's on the Front End Troubleshooting board should be off
except for DS9 and DS10, +25V supply for Attenuator A and Attenuator B.
Refer to Figure 4-12.
Keysight N9010A EXA Service Guide 159